Modern computing and control systems such as those found in aircraft and spacecraft typically include multiple sensing and/or processing components that are interconnected by a data network. Systems used in a typical avionics environment include flight management systems, air data computers, engine and air sensors, flight control systems, cockpit instrumentation and the like.
As the various computing systems used in these environments become increasingly capable, wideband data communications technologies have evolved to support faster data transfer rates between components and systems in many aerospace, industrial, transportation and other settings. The IEEE 1394b standard, for example, describes a bus implementation that supports data transfer speeds of 800 Mbps or higher over a serial connection. Other wideband data connection technologies providing high-speed data transfer include fiber data definition interface (FDDI), asynchronous transfer mode (ATM), Fiber Channel, Fast Ethernet and the like.
Even as new data communications technologies become increasingly prevalent, however, legacy systems based upon older technologies continue in widespread use. Many of these systems remain in operation due to their high reliability, and due to the relatively long periods of time often required to design, build and obtain government certification for newer systems. Systems and components designed to communicate using the MIL-STD 1553 standard, for example, have been widely deployed in aviation, space and other environments for many years. MIL-STD 1553 networks typically include a bus controller (BC) that controls traffic on a redundant bus that interconnects various remote terminal (R/T) client nodes. MIL-STD 1553 generally specifies that data is transferred between nodes in packets of not more than thirty-two data words (with each word including sixteen data bits and four control bits) across redundant twisted-pair wires with a data rate on the order of 1 MHz. The MIL-STD 1553B standard (which was a revision of earlier MIL-STD 1553 standards) was released as a tri-service/NATO standard in 1978, and is widely available.
It is generally desirable for the legacy and non-legacy components within an aircraft, spacecraft or other environment to share data and otherwise interoperate with each other. In particular, it is generally desirable to interface legacy components with newer bus technologies to take advantage of the increased bandwidth available, and to eliminate the need to provide legacy wiring throughout the vehicle or other environment. Often, however, difficulties arise in interfacing older “legacy” systems to newer technologies. MIL-STD 1553 components, for example, are highly reliable, yet generally incompatible with newer wideband technologies without significant modification. Although several products are available to interface legacy components to newer data networks, problems often remain in implementation of these products. As an example of a design difficulty to be overcome, MIL-STD 1553 typically specifies that each transmitting component receive a “handshake” response from the receiving component within fourteen microseconds of the original data transmission. While this requirement is relatively easy to meet on a conventional MIL-STD 1553 bus, it is often difficult to meet in practice when legacy components communicate across other types of data connections. In particular, the fourteen microsecond handshake period limits the ability to locate bus controllers and remote terminals on separate bus segments, thereby limiting design flexibility. Accordingly, difficulties remain in achieving true integration between the various computing systems and components operating within an avionics or other environment. Moreover, the cost, weight and complexity of providing separate legacy and wideband networks can present significant issues in highly demanding environments.
It is therefore desirable to allow legacy systems such as those based upon MIL-STD 1553 to communicate across newer high-speed data buses such as those based upon IEEE 1394 and other standards. Further, it is desirable to use high-speed data buses to interconnect legacy bus controllers and remote terminals without requiring additional cabling or excessive modifications to the legacy components. It is therefore highly desirable to create systems and methods for interfacing legacy equipment to high-speed data buses. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.